newbie insight
I just finished my front axle overhaul last weekend, and it wasn't too much trouble. I've never tackled this extensive a job before, and I'm not an experienced mechanic; however, I'm a "while you're in there" kind of guy, and knowing that my USPS inner seal had gone, I decided I might as well do the whole thing.. The job was really straightforward with the FAQs and the FSM, and it probably took me a total of 9 - 10 hours including rotor and brake pad replacement, cleaning the ABS sensors (1/2
job) and bleeding the brakes. As many have mentioned, the most time consuming thing on my end was cleaning out all of the old slop (and I spent quite a while trying to get the USDS birf off the axle -- that darned snap ring was a pain in my arse). Romer's FAQ recommends 4 rolls of shop towels and 4 cans of brake cleaner, but I went with 6 of each and was happy to have a little extra there as well.
Long story short, I'm really glad I decided to replace all of the bearings and seals; once I got into the job, I noticed that my wheel bearing races were a little pitted in places (not too bad), and my trunion/knuckle bearing inner races were pretty severely ovalized
You asked if it's easy to recognize damage before splurging on a full compliment of parts. In short, yes. Both of my bearing issues were very easy to recognize/diagnose, so if you wanted to wait to purchase these items until after you ascertain their condition, you could do so. My rig is a daily driver, so I'm glad I had almost everything on hand so I could get things back together quickly
I didn't purchase the trunion bearings up front, but luckily, I have Kurt at Cruiser Outfitters just a few miles away. Kurt mentioned that, given the fairly low cost of the knuckle bearings, he's always a little surprised that more people don't purchase them up front -- they bear a ton of weight and are easy to replace.
If you're worried about the cost of a front axle kit, I would definitely give CDan or Kurt at Cruiser Outfitters a call. I won't mention specific prices here, but both are much less expensive than what just about any other dealership will offer, and even though Kurt's kit doesn't come in little red boxes, he provides the exact same Koyo bearings for much less (in fact, the local dealer's kit cost over three times as much and included a mix of Koyo bearings with the slightly less expensive Timken inner wheel bearings
).
I hope that helps some. Feel free to PM me with any questions.
Cheers
I know mine should probably be done in the not so distant future. 
